{0,3} ensures 3 or less chars from 8th position (0,3 implies remove only if present and hence also removes 1/2/3 chars from 8th position) i.e match and remove minimum 0 chars(for no chars) and maximum 3 chars

If you want exactly only 3 chars to removed from 8th position use {3} but it wont remove chars from 8th position if there are less than 3 chars, eg: